Hundreds of factory workers grouped under the Alliance of Greater Tangerang Residents (Altar) rallied in Tangerang regency on Wednesday, calling for an end to "oppression" in the workplace.

They said the rally, which began in Curug district and ended in Cikupa, was a "warmup" ahead of the commemoration of May Day on May 1.

"We handed out a written statement to workers in seven industrial areas between Curug and Cikupa," said rally coordinator Koswara.

He said oppression by employers appeared in many forms, including underpayment, banning workers' unions and the dismissal of unionized employees, and added that things could get worse for workers if the government raised fuel prices.

"Workers will stage a massive rally in protest against the government's plan to raise fuel prices. We also demand the government eliminate the outsourcing recruitment system," he said.